Author(s)

Haley R. Tunna¹, Judit E. G. Smits², Sean M. Rogers¹, Leland J. Jackson^1*

¹Department of Biological Sciences, University of Calgary, Calgary, Canada.
²Ecosystem & Public Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, Canada.

Ecological impacts of contaminants on population patterns in wild fish are impacted by many contaminants that readily enter aquatic systems. Responses to toxicants by individuals in lab studies generally do not predict population level consequences in natural systems. Trace levels of contaminants are present in all major rivers in southern Alberta, Canada, with concentrations higher down-stream of anthropogenic inputs like agricultural land-use and inputs of municipal wastewater effluents. Longnose dace (Rhinichthys cataractae) were used as a sentinel species to study field-based population-level responses to contaminants. We hypothesized that biomarker activity, triggered by contaminant exposure, should increase downstream of anthropogenic inputs in two southern Alberta rivers, with corresponding relations between biomarker activity and sex ratios, after accounting for age structure. Liver detoxification (ethoxyresorufin-O-deethylase activity = EROD) measured at reference and exposed sites on each river differed significantly in only the Bow River system. Sex ratios varied more downstream of anthropogenic inputs than upstream, but the direction of sex ratio bias was inconsistent and temporally dynamic. Sex ratios correlated with liver detoxification in only the Bow River. Taken together, these results suggest that contaminants alter sex ratios in long-nose dace, but that there is variation in anthropogenic stressors among rivers.

Longnose Dace, Rhinichthys cataractae, EROD, Cytochrome P4501A, Ecotoxicology, Alberta

Tunna, H. , Smits, J. , Rogers, S. and Jackson, L. (2016) Detoxification Efforts in Longnose Dace (Rhinichthys cataractae) Exposed to Municipal and Agricultural Inputs. Journal of Environmental Protection, 7, 253-267. doi: 10.4236/jep.2016.72022.